title: Transcriptomic and epigenetic changes in early liver steatosis associated to obesity: effect of dietary methyl donor supplementation.
abstract: Non-alcoholic fatty liver disease is a primary hepatic manifestation of obesity and an important adverse metabolic syndrome trait. Animal models of diet-induced obesity promote liver fat accumulation putatively associated with alterations in epigenetic profile. Dietary methyl donor-supplementation may protect against this disturbance during early developmental stages affecting the molecular basis of gene regulation. The aim of this study was to investigate the transcriptomic and epigenetic mechanisms implicated in liver fat accumulation as a result of an obesogenic diet and the putative preventive role of dietary methyl donors. Forty-eight male Wistar rats were assigned into four dietary groups for 8 weeks; control, control methyl-donor-supplemented with a dietary cocktail containing betaine, choline, vitamin B12 and folic acid, high-fat-sucrose and high-fat-sucrose methyl-donor-supplemented. Liver fat accumulation induced by a HFS diet was prevented by methyl donor supplementation in HFS-fed animals. A liver mRNA microarray, subsequently validated by real time-qPCR, showed modifications in some biologically relevant genes involved in obesity development and lipid metabolism (Lepr, Srebf2, Agpat3 and Esr1). Liver global DNA methylation was decreased by methyl donor supplementation in control-fed animals. Methylation levels of specific CpG sites from Srebf2, Agpat3 and Esr1 promoter regions showed changes due to the obesogenic diet and the supplementation with methyl donors. Interestingly, Srebf2 CpG23_24 methylation levels (-167 bp and -156 bp with respect to the transcriptional start site) correlated with HDLc plasma levels, whereas Esr1 CpG14 (-2623 bp) methylation levels were associated with body and liver weights and fat content. Furthermore HFS diet-induced liver fat accumulation was prevented by methyl donor supplementation. In conclusion, both obesogenic diet and methyl donor supplementation modified the mRNA hepatic profile as well as the methylation of specific gene promoters and total DNA.
authors.affiliation: Department of Nutrition, Food Sciences and Physiology, University of Navarra, Irunlarrea 1, 31008 Pamplona, Navarra, Spain. Electronic address: pcordero@alumni.unav.es.
authors.forename: Paul
authors.initials: P
authors.lastname: Cordero
authors.forename: Javier
authors.initials: J
authors.lastname: Campion
authors.forename: Fermin I
authors.initials: FI
authors.lastname: Milagro
authors.forename: J Alfredo
authors.initials: JA
authors.lastname: Martinez
mesh_terms: D000818:Animals; D001483:Base Sequence; D015415:Biomarkers; D001835:Body Weight; D018899:CpG Islands; D019175:DNA Methylation; D019587:Dietary Supplements; D044127:Epigenesis, Genetic; D005234:Fatty Liver / Q000150:complications* / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D023061:Gene Order; D008099:Liver / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D009765:Obesity / Q000209:etiology*; D051381:Rats; D059467:Transcriptome
chemical_list: D015415:Biomarkers
keywords: ALT; ANOVA; AST; Benjamini–Hochberg false discovery rate; CIFA; DNA methylation; FDR-BH; FFA; Fatty liver; Gene expression; HFS; High-fat sucrose diet; Methyl donor supplementation; NAFDL; NASH; Obesity; RMA; RT-qPCR; alanine transaminase; analysis of variance; applied pharmacobiology center; aspartate transaminase; free fatty acids; high-fat-sucrose; non-alcoholic fatty liver disease; non-alcoholic steatohepatitis; real time polymerase chain reaction; robust multichip average